Substrate carrier having drip edge configurations

ABSTRACT

Substrate carrier can have drainage area leading the liquid away from the substrates, so that liquid droplet can be channeled away from the substrate area. The drainage area can include tilted lines and surfaces toward the ground away from the substrates. The carrier can further have drainage area leading the liquid to an end of the carrier, which then can be channeled to the ground without being free fall to the ground.

This application claims priority from U.S. provisional patentapplication Ser. No. 61/625,083, filed on Apr. 17, 2012, entitled“Substrate carrier having drip edge configurations”, which isincorporated herein by reference.

BACKGROUND

In semiconductor processing, a large number of semiconductor substratesare processed in a semiconductor facility. For example, integratedcircuit devices are fabricated on circular single crystal siliconsubstrates. Solar cells are typically fabricated in square orrectangular substrates, either single crystal silicon or polycrystallinesilicon. The substrates are stored in carriers, which are designed tohold each substrate separately without touching each other.

During single substrate processing, individual substrates are broughtfrom the carriers to a processing chamber, where each substrate isprocessed separately. During batch processing, such as a wet etchprocess, multiple substrates are transferred to a process carrier, whichsupports the substrates with adequate separate between the substrates toenable uniform processing of all substrates within the carrier. Thecarrier is then submerged in a tank filled with chemical liquid, whichcan etch all substrates at a same time.

FIGS. 1A-1C illustrate an exemplary prior art process carrier for a wetprocessing. In FIG. 1A, a carrier 100 is shown, supporting substrates110. The carrier 100 comprises two end plates 120, together with anumber of rods 130. The rods are spaced as to allow the substrates to bepositioned between the rods. The carrier 110 can comprise side rods forsupport the sides of the substrates, and bottom rods for support thesubstrate bottom. Option top rods can be included, for example, toprevent dropping of the substrates during movements. The rods 130 cancomprise teeth 135, which can separate the substrates.

FIG. 1B shows a detailed of a portion of a rod 130 with teeth 135. Theteeth comprise a cylindrical shape, disposed in a horizontal direction.The separation of the teeth is large enough to accommodate the substrate110. During liquid processing, droplets 140 can be adhered to thecarrier surfaces, such as on the surfaces of the tooth 135A (FIG. 1C).When wet processing is completed, the carrier is removed from the liquidtank. The droplets 140 can migrate along the surface of the teeth, andpotentially dropping on the substrate 110, forming contaminated spot145.

SUMMARY

In some embodiments, systems and methods are provided for reducingliquid contamination in substrates supported by a carrier. For example,after a wet process, the carrier can have liquid accumulated on theirsurfaces. The carrier can be configured to reduce or eliminate thedripping of the liquid onto the substrates, which can potentialcontaminate the substrate surfaces.

In some embodiments, the carrier can have drainage area leading theliquid away from the substrates, so that any droplet formation andreleased would fall outside of the substrate area and not on thesubstrates. The drainage area can include tilted lines and surfacestoward the ground away from the substrates. The drainage area can avoidtrappable configurations near or in the substrate area, such as a pointshape in a space defined between two substrates, a horizontal line orsurface in the space defined between two substrates, or a downwardfacing line or surface in the space defined between two substrates.

In some embodiments, the carrier can have drainage area leading theliquid to an end of the carrier, which then can be channeled to theground without being free fall to the ground. The channeling of liquiddroplets can avoid the splatter of the liquid, thus can reduce oreliminate potential substrate contamination.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C illustrate an exemplary prior art process carrier for a wetprocessing.

FIGS. 2A-2E illustrate exemplary surface configurations that canaccumulate and drop liquid droplets according to some embodiments.

FIGS. 3A-3C illustrate exemplary slanted configurations for the teeth ofa substrate carrier according to some embodiments.

FIGS. 4A-4B illustrate an exemplary carrier having a slanted teethconfiguration according to some embodiments.

FIGS. 5A-5D illustrate another exemplary carrier having a slanted teethconfiguration according to some embodiments.

FIGS. 6A-6C illustrate exemplary rod configurations according to someembodiments.

FIGS. 7A-7D illustrate exemplary cross sections of a rod according tosome embodiments.

FIGS. 8A-8B illustrate an exemplary carrier according to someembodiments of the present invention.

FIGS. 9A-9C illustrate exemplary carrier configurations according tosome embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In some embodiments, the present invention discloses carrierconfigurations to reduce or eliminate liquid droplet contamination, forexample, occurring after a wet processing. The carrier configurationscomprise drip edges leading away from the substrate area, preventing theliquid droplets from falling on the substrate surfaces.

In some embodiments, the present invention recognizes that downwardtilted, such as vertical, surfaces or paths, especially within the areaof the substrate surface, can accumulate droplets, which then can droponto the substrate to contaminate the substrate. In addition, horizontalsurfaces can accumulate droplets, thus can potentially dropping liquidon the substrate.

FIGS. 2A-2E illustrate exemplary surface configurations that canaccumulate and drop liquid droplets according to some embodiments. InFIG. 2A, a vertical surface 210 is shown, where a droplet 240 can rundown the vertical surface 210, for example, under gravitation force, toaccumulate at the bottom of the surface 210. The droplet 240 can collectfurther liquid along the way, and can become large enough to drop fromthe vertical surface 210. If the droplet 240 is formed in a vicinity ofthe substrate surface, the droplet can fall on the substrate, generatingcontamination spots.

In FIG. 2B, a curve surface 212 is shown, comprising multiple verticalpaths 222 for droplet traveling. A droplet 242 can run down the verticalpath 222, for example, under gravitation force, to accumulate at thebottom of the surface 212. The droplet 242 can collect further liquidalong the way, and can become large enough to drop from the verticalsurface 212.

In FIG. 2C, a curve surface 214 is shown, comprising multiple paths 224for droplet traveling. A droplet 244 can run down the vertical path 224,for example, under gravitation force, to accumulate at the bottom of thesurface 214. The droplet 244 can collect further liquid along the way,and can become large enough to drop from the vertical surface 214.

In FIG. 2D, a curve surface 216 is shown, comprising multiple paths 226and 227 for droplet traveling. A droplet 247 can run down the verticalpath 227, for example, under gravitation force, to accumulate at thebottom of the surface 216. The droplet 247 can follow the curvature path227 away from the substrate, thus causing no potential damage to thesubstrate. Alternatively, another droplet 246 can run down the verticalpath 226, collecting further liquid along the way, and can become largeenough to drop from the vertical surface 216. Since the vertical surface216 is likely to be in a vicinity of the substrate surface, the dropletcan fall on the substrate, generating contamination spots. Thus thecurve surface 216 can reduce potential contamination as compared to flatsurface 210 and to curve surface 212 or 214. However, in certain cases,contamination droplets can occurs, e.g., along path 226 on curve surface216. Thus substrate carriers without vertical surfaces or vertical pathsare preferred. In some embodiments, the present invention disclosesmethods and apparatuses for substrate carriers without vertical surfacesor vertical paths, especially the surfaces or paths that are positionedwithin the substrate area.

In FIG. 2E, a horizontal surface 218 is shown. A droplet 248 canrandomly occur on the surface 218 and drop onto a substrate surface.Thus substrate carriers without horizontal surfaces are preferred. Insome embodiments, the present invention discloses methods andapparatuses for substrate carriers without horizontal surfaces,especially the surfaces or paths that are positioned within thesubstrate area.

In some embodiments, carrier structures, and methods to use the carrierstructures, are provided to avoid the potential contamination caused byliquid droplets falling on the substrates. The carrier structures can beconfigured to avoid the accumulation points, for example, caused by adownward tilted line or surface, which are positioned near or in a spacedefined by two adjacent substrates.

In some embodiments, the carrier structure can be configured so thatliquid droplets are drained by gravitation force away from thesubstrates, or away from a space defined by two adjacent substrates. Thecarrier structure can be configured so that the falling of liquiddroplets from the carrier structure would not land on the substratesurface. For example, the carrier structure can be configured so thatany liquid accumulation point are positioned away from the substrates,or away from a volume defined by the multiple substrates. The carrierstructure can be configured as not to have a point, a horizontal line ora horizontal surface within the substrates, or within a volume definedby the multiple substrates, which can trap the liquid droplets.

In some embodiments, the carrier structure can include paths so that theliquid droplets travel away from the substrates. For example, thecarrier structure can have tilted lines or surfaces toward the bottom ofthe substrates and away from the substrates.

In some embodiments, the carrier structure can include paths so that theliquid droplets travel to the ground. The ground paths can avoidsplattering of the liquid, which can further reduce substratecontamination. For example, the carrier structure can have tilted linesor surfaces toward one end of the carrier structure, and then channelsat the end to the ground. A side structure of the carrier structure canhave tilted lines or surface toward an end structure so that thedroplets can travel to the end structure. The end structure can havechannels or paths to guide the liquid to the floor, without anyaccumulation of the liquid on the carrier structure.

In some embodiments, the present invention discloses substrate carrierscomprising multiple teeth which are configured to comprise drip edgesleading away from the tips of the teeth. For example, the substratecarriers can include side structures such as rods or plates, withprotruding teeth which can protrude to a space between two adjacentsubstrates for separating the two adjacent substrates.

In some embodiments, the substrate carriers comprise teethconfigurations having slanted angles for teeth surfaces and teeth lines.In some embodiments, the teeth configurations do not comprise verticalsurfaces or lines, at least in the teeth area that can contact thesubstrate. The slanted angles can be directed away from the substrate,or can be leading to another slanted angle which is directed away fromthe substrate.

FIGS. 3A-3C illustrate exemplary slanted configurations for the teeth ofa substrate carrier according to some embodiments. In FIG. 3A, a tooth390 protrudes toward a substrate 310 so that a portion of the tooth 390is positioned within the area of the substrate. The tooth 390 comprisesslanted angles 380, so that droplets 340 travel along a slanted path 320away from the substrate 310. The slanted angles extend outside thesubstrate area, so that the droplets do not fall on the substratesurface.

In FIG. 3B, a tooth 330 in the shape of a pyramid having a quadrilateralbase (4 side polygon) is protruded toward the substrate 310. The tooth330 comprises slanted surfaces 392 and 394, which can direct dropletstoward a slanted line 382, where droplets can be drained outside thesubstrate area. Sharp corners or rounded corners, e.g., 372 and 374, canbe used, to facilitate the running of droplets toward the outside of thesubstrate area.

In some embodiments, the present invention discloses teethconfigurations comprising bottom slanted angles, e.g., slanted surfaceor lines, toward outside of the substrate area. The top angles can beslanted toward the inside of the substrate area, with drip edge leadingback to the outside, for example, at the bottom slanted angles.

In FIG. 3C, tooth 332 is further pointing upward, forming all downwardslanting surfaces and lines toward the outside area of the substrate310. When connecting to a side structure, such as a rod or a plate, thetooth 332 can have the top edge shorter than the bottom edge. Othershapes can be used, such as a cone shape or pyramid shape with differentpolygon base.

In some embodiments, the present invention discloses carriers havingteeth configurations comprising slanted angles, e.g., slanted surface orlines, toward outside of the substrate area. The teeth can be configuredon side plates or on side rods, sandwiching the substrates. The slantedangle can be greater than about 10 degrees, or greater than about 30 or45 degrees.

FIGS. 4A-4B illustrate an exemplary carrier having a slanted teethconfiguration according to some embodiments. FIG. 4A shows a perspectiveview and FIG. 4B shows a side view of a side of a carrier 400,comprising a side plate 430 having a plurality of teeth 435. The teeth435 are arranged in two rows for supporting substrates 410. The teeth ina row are configured to separate the substrates. For example, the teethcan comprise a pyramid shape, with the tips of two nearby pyramids arewider than the thickness of the substrate. The bottom portions of thenearby pyramids are narrower than the thickness of the substrate. Thusthe substrate can be resting against the edges of the pyramid teeth.Alternatively, the bottom portions of two adjacent pyramids can be widerthan the thickness of the substrate, and the substrate can be restingagainst the side plate 430.

FIGS. 5A-5D illustrate another exemplary carrier having a slanted teethconfiguration according to some embodiments. FIG. 5A shows a perspectiveview of a carrier 500 and FIGS. 5B-5C shows different side views ofdifferent carriers 500-504, comprising two rods having a plurality ofteeth. FIGS. 5A and 5B show a same carrier 500, and FIGS. 5C and 5D showtwo different carriers 502 and 504, having some modifications fromcarrier 500. The rods 530 comprise teeth 532A, 532B, 535A and 535B arearranged periodically along the rods for supporting substrates 510,configured to separate the substrates. For example, the teeth 532A and532B can comprise a pyramid shape, with the tips of two nearby pyramidsare wider than the thickness of the substrate. The bottom portions ofthe nearby pyramids are narrower than the thickness of the substrate510. Thus the substrate can be resting against the edges of the pyramidteeth (see FIGS. 5A and 5B). Alternatively, the teeth 535A and 535B cancomprise a pyramid shape, with the bottom portions of two adjacentpyramids wider than the thickness of the substrate 515, and thesubstrate can be resting against the rods 530 (see FIGS. 5A and 5C). Insome embodiments, the rods and teeth comprise polymeric materials, suchas plastic or polymer. The rods can comprise a core 540, for example, ametal or a steel core to enforce the rigidity of the rods.

The teeth 532A, 532B, 535A and 535B are shown to be positioned in asubstantially horizontal configuration, with the top portion slantedtoward the substrate and the bottom portion slanted away from thesubstrate. Thus a liquid droplet can travel along the slanted portionsand ultimately drain away from the substrate. For example, a droplet cantravel form the top portion, connecting to the bottom portion, and thenfollowing the bottom portion away from the substrate.

FIG. 5D shows an exemplary configuration of a rod 536, comprising theteeth 537 pointing upward. The slanted portions of the teeth are thendirected away from the substrate, thus droplets can all travel away fromthe substrate area. The rod 536 can be the same rod 530, with anadditional rotation along the center of the rod, so that the pyramidteeth are positioned in an upward slanted configuration. The rod 536 canbe different from the rod 530, for example, with longer pyramid (e.g.,taller or higher pyramid) to accommodate the substrate separationpurposes. Other configurations are also within the scope of the presentinvention, such as teeth configuration having polygon base, teethconfiguration having rounded corners, etc.

In some embodiments, the rod can comprise different configurations, forexample, to optimize the drip edge of droplets. In some embodiments,symmetrical rods and symmetrical teeth can be used, for example, forease of fabrication and minimizing rod warpage.

FIGS. 6A-6C illustrate exemplary rod configurations according to someembodiments. In FIG. 6A, a rod 630 or 631 comprises a circular crosssection with enforcement core. The teeth can comprise a pyramid shape,with sharp corner (rod 630) or rounded corners (rod 631). In FIG. 6B, arod 632 or 633 comprises an elliptical cross section with enforcementcore. The teeth can comprise a pyramid shape, with sharp corner (rod632) or rounded corners (rod 633). The elliptical shape can comprise alonger axis in a vertical direction, to generate a larger slanted anglefor the teeth surface of lines. Alternatively, the elliptical shape cancomprise a shorter axis in a vertical direction (not shown), to providebetter stability and less deflected angle to the teeth. In FIG. 6C, arod 634 or 635 comprises a square cross section or a quasi-square crosssection (e.g., a diamond shape or a square with rounded corners) withenforcement core. The teeth can comprise a pyramid shape, with sharpcorner (rod 634) or rounded corners (rod 635). The square shape cancomprise a diagonal line aligned in a vertical direction, to generate alarger slanted angle for the teeth surface of lines. The rod profilescan have increased rigidity, for example, with respect to the bending inthe two principal directions, e.g., vertical and horizontal.

Other configurations can be used. The rods are shown with the pyramidteeth disposed in a substantially horizontal direction, but anydirection can be used, such as an upward pointing pyramid. In addition,other teeth configurations can be used, such as cone shape teeth orcylindrical shaper teeth with cone or pyramid tip. For cylindrical shapeteeth, the teeth can be position upward to prevent horizontal line.

In some embodiments, non symmetrical cross section rods can be used, forexample, to optimize the slanted angle of the drip edge for thedroplets.

FIGS. 7A-7D illustrate exemplary cross sections of a rod according tosome embodiments. In FIG. 7A, a circular rod can comprise teeth having acurve upper portion 737, such as an elliptical surface. The ellipticalsurface can minimize the possibility of the droplets to be falling fromthe top of the teeth to the substrate, offering better tendency for thedroplets to follow the bottom portion toward the outside area. In FIGS.7B and 7C, a triangular cross section rod can be used. Otherconfiguration can be used, such as rounded corners, or upward pointingteeth. In FIG. 7D, a rod is shown, having a quasi square cross section,together with bow teeth.

FIGS. 8A-8B illustrate an exemplary carrier according to someembodiments of the present invention. A carrier 800 comprises two endplates 820 coupled to a plurality of rods 830, 835, 840, 845, 850, and860 for supporting the substrates 810. The rods 830 and 835 are disposedin one side, and rods 840 and 845 are disposed in an opposite side,sandwiching the substrates 810. Rod 860 is disposed under thesubstrates, for supporting the substrates. Rod 850 is optional, disposedon top of the substrates to prevent any movement of the substrates. Rod850 can be removable, for removing the substrates. Rods 830, 835, 840and 845 comprise pyramid teeth 870, for separating the substrates. Rods850 and 860, as shown, do not comprise teeth. The configuration isexemplary, and any variations can be used, such as rods 850 and/or 860can comprise teeth, or one or some of rods 830, 835, 840 and 845 do notcomprise teeth. Further, additional rods can be added. The teeth can beconfigured to comprise slanted drip edge away from the substrates toprevent, eliminate or minimize contamination, for example, caused bydroplets falling on the substrate from a carrier component, such as theteeth.

In some embodiments, the rods can be configured to further minimizecontamination. The present drip edge configurations for the teeth canlead droplets to the rods, which is disposed outside the substrate area.In some embodiments, the present invention discloses a drip edge for therods, further leading the droplets away from the substrates.

FIGS. 9A-9C illustrate exemplary carrier configurations according tosome embodiments. In FIG. 9A, a carrier 900 comprises a plurality ofrods 930, which can accumulate droplets accumulated from the teeth dripedges. In FIG. 9B, a carrier 902 comprises a plurality of rods thatcomprise a drip edge 932, disposed at a slanted angle. Thus the dropletsaccumulated at the rods will be further leading away from the substrate,and accumulated at the end plate of the carrier. The end carrier canalso comprise drip edges to further leading the droplets to the bottomportion of the end plate. In FIG. 9C, a carrier 904 comprises aplurality of rods 934 that are disposed at a slanted angle. The teethcan be rotated with an appropriate angle, for example, to accommodatethe substrates. Alternatively, the same rods can be used. Thus thedroplets accumulated at the rods will be further leading away from thesubstrate, and accumulated at the end plate of the carrier. The slantedangle can be less than about 50 degrees, or less than about 40 or 30degrees. The slanted angle can be greater than about 5 degrees, orgreater than about 10 or 20 degrees.

In some embodiments, methods for using the substrate carriers areprovided. One or more substrates can be placed in a carrier, with thesubstrates separated by a portion of the carrier that is protrudedbetween every adjacent substrate. For example, the substrates can beseparated by multiple teeth, which are secured to a side structure suchas a rod or a plate. The carrier can include tilted surfaces or linesaway from the substrate area to prevent liquid droplets dropping on thesubstrates.

The carrier and the substrates can be wet processed, for example, bysubmerged in a tank of liquid for cleaning or for wet etching. Thecarrier and the substrates can be sprayed with a liquid. After wetprocessing, the carrier and the substrates can be removed from theliquid environment to be dried, for example, by circulating hot gas.Before the substrate and the carrier are dried, any liquid droplet canbe drained away from the substrates, preventing contamination to thesubstrates.

What is claimed is:
 1. A carrier for supporting one or more substrates,the carrier comprising: at least one first structure; at least onesecond structure, wherein the second structure is secured to the firststructure, wherein the second structure is partially protruded to aspace defined by two adjacent substrates for separating the two adjacentsubstrates; wherein the second structure is configured so that liquiddroplets are drained by gravitation force away from the substrates.
 2. Acarrier as in claim 1 wherein the second structure comprises paths sothat the liquid droplets travel away from the substrates.
 3. A carrieras in claim 1 wherein the second structure comprises tilted lines orsurfaces toward the bottom of the substrates and away from thesubstrates.
 4. A carrier as in claim 1 wherein the second structure doesnot have a point, a horizontal line or a horizontal surface within thespace, which can trap the liquid droplets.
 5. A carrier as in claim 1wherein the first structure is configured so that liquid droplets aredrained by gravitation force toward one end of the first structure.
 6. Acarrier for supporting one or more substrates, the carrier comprising:at least one first structure; at least one second structure, wherein thesecond structure is secured to the first structure, wherein the secondstructure is partially protruded to a space defined by two adjacentsubstrates for separating the two adjacent substrates; wherein thesecond structure comprises surfaces tilting away from the substrates sothat liquid droplets are drained by gravitation force away from thespace.
 7. A carrier as in claim 6 wherein the protruded portion of thesecond structure comprises a pyramid or a cone shape.
 8. A carrier as inclaim 7 wherein the pyramid comprises an edge at the bottommost section.9. A carrier as in claim 7 wherein the pyramid or the cone shapecomprise an apex pointing upward from the first structure.
 10. A carrieras in claim 6 wherein the first structure comprises a plate.
 11. Acarrier as in claim 6 wherein the first structure comprises a rod.
 12. Acarrier as in claim 6 wherein the first structure comprises a plasticrod re-enforced with a metal core.
 13. A carrier as in claim 12 whereinthe cross-section of the rod comprises an elliptical shape.
 14. Acarrier as in claim 12 wherein the cross-section of the rod comprises aquasi-square shape.
 15. A carrier as in claim 6 wherein the firststructure comprises a slanted angle.
 16. A carrier as in claim 6 whereinthe first structure comprises an L shape having one side partiallycovering a side of the carrier and one side partially covering thebottom of the carrier.
 17. A carrier as in claim 6 wherein the firststructure is disposed at a side of the carrier, and the carrier furthercomprises a bottom structure for supporting the substrates at the bottomof the carrier.
 18. A method comprising: supplying one or moresubstrates to a carrier, wherein the carrier comprises a structureprotruded to a space defined by two adjacent substrates for separatingthe two adjacent substrates, wherein the structure comprises surfacestilting away from the substrates; wetting the carrier and the substrateswith a liquid, wherein the liquid droplets are drained by gravitationforce away from the substrates.
 19. A method as in claim 18 whereinwetting with a liquid comprises raising the carrier and the substratesfrom a container filled with the liquid.
 20. A method as in claim 18further comprising: drying the substrates.